1. Field of the Invention
The present invention relates to optical disc recording apparatuses that record information on an optical disc by means of an LD (laser diode) that forms pits in the optical disc through the application of a write pulse of a previously set type. More particularly, the present invention relates to a DVD recorder that records information on a CD (Compact Disc) or DVD (Digital Versatile Disc).
2. Description of Related Art
With the recent development of digital technology, optical disc recording apparatuses that adopt an optical disc such as a CD (Compact Disc) and a DVD (Digital Versatile Disc) as a recording medium for recording information such as music, video, and software have been increasingly widespread. In this optical disc recording apparatus, information is recorded in the form of pits formed by laser light emitted from a light source such as an LD (laser diode) and shone onto a recording layer of an optical disc on which tracks are formed in a concentric pattern, and information is reproduced based on the light reflected from the recording layer.
Power and the shape of pulse applied to the LD that forms pits greatly influence the recording quality (the shape of the formed pits). It is for this reason that various methods and apparatuses for forming pits of good quality have been proposed. For example, an optical disc apparatus that first preheats a recording layer to a temperature of less than the pit formation start temperature by irradiating it with laser light with a preheating pulse representing power that is greater than the reproducing power but equal to or smaller than 80% of the recording power, and then heats the recording layer to or above the pit formation start temperature by irradiating it with laser light with a main pulse representing the recording power has been disclosed (JP-A-2005-339672).
However, in the conventional optical disc recording apparatuses including the abovementioned optical disc apparatus, the rise in temperature of the LD leads to a decrease in the amount of emitted laser light (hereinafter, such a decrease will be referred to as “droop”). This may cause degradation of pit quality.